In order to improve the transport efficiency and reliability, a transport network usually adopts a ring network. Taking a T-MPLS shared protection ring (TM-SPRing) as an example, a logic adjacency relation is established between each two nodes of the ring network, and the establishing of the connection relation between corresponding nodes is not limited by physical devices and a media access control (MAC) topology. The connection between the neighboring nodes is called a span, and the span is a bi-directional connection (possibly being a physical link or a logic connection). A transporting channel entity configured to transport service data flows between nodes on the ring is implemented by a group of LSPs based on the T-MPLS. The TM-SPRing adopts a double-ring structure, and flowing directions of the service data flows of the two rings are opposite, the two rings include a working ring (working direction) and a protection ring (reverse direction of the working direction), each ring may establish a plurality of LSPs according to the amount demand of services, so as to assign different LSPs to different service data flows. The protection of the TM-SPRing is performed for the span between the neighboring nodes, and is implemented through an OAM function of the span.
When the span has a failure, in order to prevent the span between the neighboring nodes from failing, an entire protection mechanism needs to be confirmed, so as to quickly protect the span failure, and correctly and effectively transport the service data flow. Currently, the common protection mechanism using the shared protection ring has two switching mechanisms, namely, a steering manner and a wrapping manner. The largest difference between the steering manner and the wrapping manner is that after the span failure occurs, the nodes initiating the switching of the service data flow are different, where in the steering manner, the node initiating the switching of the service data flow is a source node of the service data flow, but in the wrapping manner, the node initiating the switching of the service data flow is a failed span neighboring node. The wrapping manner has a short switching starting time, and has low corresponding packet loss, but a switched wrapping protection path is not an optimal routing. A steering protection path of the steering manner is the optimal routing, but the steering manner has a long switching starting time and high corresponding packet loss.
An existing resilient packet ring (RPR) network adopts a combination protection solution of the wrapping manner and the steering manner, and the implementation of the solution is performed according to the following steps.
Firstly, after the failure occurs, a failed span neighboring node detects the failure, and immediately performs the switching operation in the wrapping manner, so that a first service data flow steer clear of the failed span, that is, the affected first service data flow (the service data flow that is about to pass by the failed span from the working direction) is wrapped to the other ring for being transported, and meanwhile, the failed span neighboring node bi-directionally sends a protection request message including the failed span information.
Next, when receiving the protection request message, the source node and the target node of the service data flow perform the switching operation in the steering manner, so that a second service data flow subsequent to the first service data flow is transferred to the other ring for being transported, so as to steer clear of the failed span.
A starting time of the switching action of the solution is equal to a starting time of the switching action in the wrapping manner, and the reason is that the wrapping protection solution is used in a first stage, so that the packet loss of the first service data flow is low. In addition, after the switching action in the steering manner is adopted, the final path which the second service data flow passes by is the same as the steering protection path in the steering manner, and is the optimal routing on the other ring, thereby improving the utilization of network resources, avoiding from introducing unnecessary time delay, and integrating advantages of the two solutions being the wrapping manner and the steering manner.
The inventors find the following problems during the implementation of the disclosure.
According to the description of the above two steps, the path of the service data flow is changed twice in the solution. F or the first time, the first service data flow is switched from the working path to the wrapping protection path for being transported, and for the second time, the second service data flow is switched from the wrapping protection path to the steering protection path for being transported. As compared with the steering protection path, the wrapping protection path has the path wrapping on the working ring, so it is possible that the second service data flow sent after the second time of switching reaches the target node earlier than the first service data flow sent after the first time of switching, so as to result in a disordering problem of the service data flow.
The packet transport technique aims to implement a multi-service uniform bearing platform, and needs to transport a TDM service, and the TDM service has strict demands on a time sequence.